The present invention relates to a trunk lid of an automobile, and more particularly, to a trunk lid support device for an automobile constructed to enable the trunk lid to be maintained in a stable open state.
Generally, a passenger car is equipped with a trunk at the rear side for storing spare tires and the like. The trunk is composed of a predetermined space for accommodating articles, a trunk lid for enclosing the predetermined space, and a locking device.
As shown in FIG. 1, the trunk lid is supported by the car body (B), and the trunk lid (T) is connected at one end to a gooseneck member 5. The gooseneck member 5 is coupled to the car body (B) via a first hinge 10 such that when the trunk lid (T) is pivoted via the first hinge 10, the trunk may be opened and closed.
As shown in FIG. 2, between the gooseneck 5 and the car body (B) there is a gas lifter (L) for smoothing the opening and closing operation of the trunk lid (T). The gas lifter (L) also serves to prevent the trunk lid (T) from bobbing up and down or engaging in a jerky movement from an open position to a closed position by using a predetermined force.
However, there is a problem in the conventional mechanism thus described. Power for the gas lifter (L) to support the trunk lid (T) weakens when the trunk lid (T) is opened, thus being unable to stably support the open state of the trunk lid (T), which causes the trunk lid (T) to close or vibrate by itself. Particularly, when the temperature drops down in the winter season, gas filled in the gas lifter (L) drops in pressure to further weaken the power that supports the trunk lid (T), often causing the trunk lid (T) to close by itself, potentially causing injury to a user. One of the ways to solve the aforementioned problem is to increase gas pressure in the gas lifter (L), but this causes another problem in that pressure increase in the gas lifter (L) abruptly opens the trunk lid (T) to make movement of the trunk lid (T) unstable. There is another problem in that more power is needed to close the trunk lid (T), which may cause inconvenience to a user.
As shown in FIG. 3, the length of a vertical line (R1) extending from the lengthwise extending line of the gas lifter (L) to the first hinge 10 while the trunk lid (T) is closed represents the length of the moment arm for calculating the torque provided by the gas lifter (L) when the trunk lid (T) starts to open. Likewise, the length of vertical line (R2) extending from the lengthwise extending line of the gas lifter (L) to the first hinge 10 when the trunk lid (T) is maximally opened represents the length of the moment arm for calculating the torque provided by the gas lifter (L) in order to support the open state of the trunk lid (T). If the two lengths of the moment arms (R1 and R2) are compared therebetween, the length of moment arm (R1) when the trunk lid (T) is closed is slightly longer than the length of the moment arm (R2) when the trunk lid (T) is maximally opened.
It should be apparent that the force provided to the trunk lid (T) by the gas lifter (L) is stronger when the trunk lid (T) is closed than when the trunk lid (T) is opened. Although it is natural to consider the characteristics of the gas in the gas lifter (L), it should be assumed that the same force is applied when the trunk lid (T) is in a closed and open state for the sake of easy interpretation, such that it can be noticed that the force supplied by the gas lifter (L) and the moment arm (R2) in the open state of the trunk lid (T) is smaller than the moment force supplied by the gas lifter (L) and the moment arm (R1) in a closed state of the trunk lid (T). In other words, assuming that the same amount of power is applied, the magnitude of the moment force is proportional to the length of the moment arm applied with the power, such that, even if the same amount of power is applied to the gas lifter (L), less moment force is received when the trunk lid (T) is opened than when the trunk lid (T) is closed, the moment force being formed by the power applied from the gas lifter (L).
In view of the aforesaid drawbacks, it would be desirable to provide a trunk lid support device using the gooseneck member 5 and the gas lifter (L) with more power applied to support the opened state of the trunk lid (T).
The present invention provides a trunk lid support device for an automobile adapted to further increase the moment force formed by the power supplied from a gas lifter in a state where a trunk lid is maximally opened without increasing the gas pressure of the gas lifter and without significant change to the existing structure, thus ensuring a stable open state of the trunk lid.
According to one embodiment of the invention, the device comprises a gooseneck member, one end of which is connected to a trunk lid while the other end is coupled to an automobile body via a first hinge. A gas lifter has a first end coupled to the automobile body via a second hinge and a second end coupled at a predetermined position to the gooseneck member via a third hinge. The second end of the gas lifter is coupled to the gooseneck member so that the vertical distance from the first hinge to the gas lifter when the trunk lid is fully open is longer than the vertical distance from the first hinge to the gas lifter when the trunk lid is closed.